According to this article, bassist Geezer Butler wrote the lyrics, he said he had never heard of the comic book character at the time:
Although Marvel had established that superhero in 1963, Sabbath bassist Geezer Butler, who wrote the lyrics for the iconic song, had never even heard of him in 1970.
“My parents never let me read American comics when I was growing up,” he says.
“I knew about Batman and Superman, but that’s about it. For me it was all about the Beano and the Dandy. So whenever someone’s said to me over the years: ‘Oh, didn’t you write this about the superhero?’, I’d just say: ‘Sorry, never heard of him.’”
It also talks about the story Butler imagined to go with the song:
“I can’t exactly recall what Ozzy said, but it was something like: ‘Why don’t we do a song called Iron Man, or maybe Iron Bloke’. That got me thinking about a lump of metal, and then putting it all into a science-fiction context. It all flowed from there.”
The meaning of the storyline – a self-fulfilment prophecy, mixed up with time travel – is actually quite complex. It’s about a man who goes into the future and witnesses the apocalypse. Going back to his own time, he encounters a rogue magnetic field, which turns him into a mute, steel creature. Unable to talk, he still tries to warn people about the impending end of the world, but is only mocked for his troubles. Angry and bitter, he eventually causes the devastation he’d warned everyone about. Ultimately the would-be hero becomes the villain.
“I was heavily into science fiction at the time,” Butler recalls of almost 50 years ago. “Remember, this was the era of the space race,” he says. “A lot of the stuff I was writing about was inspired by those sorts of stories. I was fascinated by what might happen to a man who’s suddenly transformed into a metal being. He still has a human brain, and wants to do the right thing, but eventually his own frustrations at the way humanity treats him drives this creature to taking extreme action. It’s almost a cry for help.
“What I always attempted to do with my science-fiction plots was to make these relevant to the modern world at the time,” Butler continues. “So I brought war and politics in. It was also an era when the whole issue of pollution was starting to get attention, and this affected my thinking quite a bit.”
